The present invention relates to a polymerizable sulfur-containing (meth)acrylate, a polymerizable composition comprising the same and an optical lens which is a cured product of the composition. More specifically, it relates to a polymerizable sulfur-containing (meth)acrylate which has a high refractive index, a great Abbe""s number and excellent light resistance, is suitable for the production of a transparent resin which rarely smells at the time of molding and is further excellent in storage stability, a polymerizable composition comprising the (meth)acrylate and an optical lens which is a cured product of the composition.
Although various kinds of organic glass have been studied as substitutes for inorganic glass, they still have many defects and completely satisfactory organic glass is yet to be obtained. For example, cured materials obtained by polymerizing monomers essentially composed of methyl methacrylate and diethylene glycol bis(allylcarbonate) are used as optical materials and lenses but their refractive indices are low at approximately 1.50.
Various studies on the introduction of a sulfur atom into the molecular structure have recently been made to improve refractive index. JP-A 1-128966 (the term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d) discloses a (meth)acrylate-based polymerizable monomer having a sulfide structure. JP-A 4-161410 discloses a polymer obtained by polymerizing and curing a (meth)acrylate-based polymerizable monomer having a dithian ring. Cured materials obtained by polymerizing and curing these polymerizable monomers have a refractive index of approximately 1.57 to 1.61 which are a little higher than the conventional cured products. Therefore, it is hardly said that they are satisfactory in terms of refractive index.
Further, JP-A 4-161411 discloses a polymer obtained by polymerizing and curing a thio(meth)acrylate-based polymerizable monomer having a dithian ring. Although this cured product has a high refractive index of 1.60 to 1.65, it has poor light resistance and emits an offensive smell at the time of molding. The thio(meth)acrylate-based polymerizable monomer also has such a problem that it is readily gelled when it is stored.
JP-A 8-12669 discloses an aromatic vinyl compound having a dithian ring. A cured product obtained by polymerizing and curing this compound has a high refractive index of 1.66 but its Abbe""s number is 31. Therefore, the improvement of its Abbe""s number is desired.
It is an object of the present invention to provide a polymerizable monomer which solves the above problems of the conventional polymerizable monomer for use as an optical material and which provides a cured product having a high refractive index, a great Abbe""s number and excellent light resistance, rarely smells at the time of molding and is further excellent in storage stability.
It is another object of the present invention to provide a specific (meth)acrylate having a dithian ring as a polymerizable monomer having the above characteristic properties.
It is still another object of the present invention to provide a polymerizable composition comprising the above polymerizable monomer.
It is a further object of the present invention to provide a cured material for use as an optical material which is a cured product of the above polymerizable composition.
It is a still further object of the present invention to provide an optical lens which comprises the above cured material.
Other objects and advantages of the present invention will become apparent from the following description.
According to the present invention, firstly, the above objects and advantages of the present invention are attained by a polymerizable sulfur-containing (meth)acrylate represented by the following formula (1): 
wherein R1 and R2 are each independently an alkylene group having 2 to 4 carbon atoms or arylene group having 6 to 12 carbon atoms, R3 is a group represented by the following formula (a): 
wherein R6 is an alkylene group having 2 to 4 carbon atoms, arylene group having 6 to 12 carbon atoms, aromatic heterocyclic group, or group represented by the following formula (b): 
wherein R7, R8, R9 and R10 are each independently a halogen atom (excluding fluorine atom) or hydrogen atom, R11 is an alkylene group having 1 to 3 carbon atoms or sulfur atom, and q is an integer of 0 to 4), R4 and R5 are each independently a hydrogen atom or methyl group, p is an integer of 0 to 6, and m and n are each independently an integer of 1 to 6, with the proviso that the above alkylene group, arylene group and aromatic heterocyclic group may be substituted with a substituent, and m and n are not xe2x80x9c1xe2x80x9d when p is xe2x80x9c0xe2x80x9d.
Secondly, the above objects and advantages of the present invention are attained by a polymerizable composition which comprises a polymerizable sulfur-containing (meth)acrylate represented by the above formula (1) in an amount of 10 to 98 wt % and other polymerizable monomer copolymerizable with the above (meth)methacrylate in an amount of 90 to 2 wt % based on the total weight of the (meth)acrylate and the monomer.
Thirdly, the above objects and advantages of the present invention are attained by a cured material for use as an optical material which is a cured product of the polymerizable composition of the present invention.
In the fourth place, the above objects and advantages of the present invention are attained by an optical lens which is the cured material for use as an optical material of the present invention.